William II of Sicily

William II of Sicily (1155-11 November 1189) was King of Sicily from 7 May 1166 to 11 November 1189, succeeding William I of Sicily and preceding Tancred of Lecce. William married his aunt Constance of Sicily to the Holy Roman Emperor Henry VI, which would eventually lead to Sicily becoming a part of the Holy Roman Empire.

Biography
William de Hauteville was born in 1155, the son of William I of Sicily and Margaret of Navarre and a scion of the Norman House of Hauteville. William became King of Sicily in 1166 on the death of his father, but he was prevented from ruling by regents until he became an adult in 1171. In February 1177, he married Joan Plantagenet, the daughter of King Henry II of England, and he married his aunt Constance of Sicily to Henry VI of Germany so that he could have the Holy Roman Empire's protection in Italy as he set his sights on foreign conquests. In July 1174, 30,000 Sicilian troops landed in Egypt, but the arrival of Saladin and his army of Ayyubids led to the Sicilians retreating in disarray. In 1180, he instead decided to campaign against the Byzantine Empire, and he laid siege to the city of Dyrrhachium (Durres, Albania), capturing it on 11 June 1185. In August, his army sacked Thessalonica and killed 7,000 soldiers and civilians after taking 3,000 losses, but on 7 November 1185 he was defeated at the Battle of Demetritzes. He abandoned Thessalonica shortly after, and in 1189 he proceeded to make peace with Emperor Isaac II of Byzantium. In November 1189, he died in Palermo before he could take part in the Third Crusade.